Circumference with Radius

The second way to do circumference (c) is a few steps more than the previous way. Here we go again...

1. Find the radius (or half of the diameter) across the circle

2. Multiply the radius (r) by two - 2r

3. Multiply your new number by pi (π)
So it will look like this...
2r x π
or...
Radius x 2 x Pi =